Electric Field Effects on the Adsorption of Dopamine Species on Ag(111): DFT Investigation of Interaction Mechanism

ROSSI-FERNÁNDEZ, ANA C.; MEIER, LORENA A.; DOMANCICH, NICOLÁS F.; CASTELLANI, NORBERTO J.

ChemistrySelect

Wiley-VCH

Año: 2020 vol. 5 p. 4728 - 4739

2365-6549

The study of interactions between dopamine (DA)and noble metal surfaces as Ag, is envisaged as a fundamental factor to attainmore efficient electrochemical sensor materials. We describe, in the frameworkof Density Functional Theory, the adsorption of four dopamine species, neutral(NDA), zwitterionic (ZDA), protonated (PDA) and deprotonated (DPDA) species onAg(111), upon the application of an external electric field (E), a fact ofpertinence for electrochemistry tests. The ZDA and PDA species show relativelylarge binding energies of about 2.9 eV to 4.6 eV and suffer a significantflatting upon adsorption, compared with DPDA and NDA. The adsorbates bindingenergy is an increasing function of the applied E for ZDA and PDA species,showing a great change when the results for positive and negative E arecompared. An electron transfer is produced from NDA, ZDA and PDA species to Ag,while in the case of DPDA an opposite behavior is obtained. As the sign of E ismodified, an increase of charge values in all DA species is observed. Thetheoretical results obtained here show that ZDA and PDA species are the mostaffected DA species upon adsorption on Ag(111) and when non-zero electric fieldsare applied.